Week 2- Pain Control Flashcards Preview

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Flashcards in Week 2- Pain Control Deck (20)
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1
Q

Action Potentials: innervated muscles

A
  1. dpolarization of nerve first
  2. propagation of stimulus along axon
  3. across neuromuscular junction
  4. across sarcolemma
2
Q

Strength-duration curve SD CURVE

A

electrical stimulus must be of sufficient STRENGTH (amplitude) and DURATION (pulse duration) to depolarize the cell and PRODUCT ACTION POTENTIAL
(how much electrical current is needed to produce an AP)

**KNOW THIS:
Depends on type of nerve

  • SENSORY NERVES: shorter pulse durations/low amplitude
  • MOTOR NERVES: longer pulse durations/high amplitude
3
Q

Rheobase & Chronaxie (of SD curve)

A

Rheobase: min STRENGTH of stimulus of long duration capable of eliciting min detectable motor response
(for min. muscle contraction)

Chronaxie: DURATION of stimulus 2x the rheobase strength able to elicit min detectable motor response. (min muscle contraction)

4
Q

Nerve size and electrode placement

A
  • when a peripheral nerve is stimulated, fibers with GREATEST DIAMETER AND LOWEST RESISTANCE are DEPOLARIZED first
  • fiber that are the CLOSEST TO THE ELECTRODES EXCITED first
  • SMALLER DIAMETER NERVE FIBERS MAY BE EXCITED FIRST before larger diameter fibers bc they might be closer.
5
Q

A Alpha

A

Diameter (micrometers): 12-20 micro-m

Function: Proprioception, motor

6
Q

A Beta

A

Diameter: 5-12 um
Function: Touch, pressure

7
Q

A Delta

A

Diameter: 2-5 um
Function: Pain, temperature

8
Q

C Dorsal Root

A

Diameter: 0.4-1.2 um
Function: Pain

9
Q

Motor unit recruitment

A

Electrically stimulated muscle contraction:
-largest diameter nerve fibers are activated first then small diameter

Voluntary Contraction: (brain move)

  • small muscle fibers to larger muscle fibers.. activate as needed GRADUALLY
  • smooth contractions

**more ampl. more unit recruitment

10
Q

Sensory Level Stimulation (frequency/ pt. response)

A

1-10 pps: tapping
25-50 pps: tingling
We 80-125 pps: tingling

11
Q

Motor Level Stimulation (frequency/ pt. response)

A

1-10 pps: twitching
25-50 pps: tetany (steady contraction)
80-125 pps: tetany (rapid fatigue)

12
Q

Nociceptive Afferents (fibers)

A
  • A delta fibers: MYELINATED. Fast pain (sharp)

- C fibers (UNMYELINATED). Slow pain (dull, aching)

13
Q

Gate Control Theory (description)

A
  • Implies the action of the SPINAL GATING SYSTEM maybe OPEN OR CLOSED, depending on the net neutral input coming from A-Beta, A-Delta, and C fibers.
  • gate CLOSED: NO nociceptive input reaches brain (pain relief)

Electrical stimulation units close gate by:
-stimulation of A-BETA FIBERS (large-diameter) when perceived a tingling sensation, prevents impulses from C AND A DELTA FIBERS (small-diameter) reaching the brain.

14
Q

Gate Control Theory (SENSORY LEVEL STIMULATION)

  • Modes
  • Indications
  • Pain Relief
  • Set up
A

*Modes: conventional, HIGH FREQUENCY, or sensory TENS

Indications: Acute pain, sub acute pain, chronic pain

Pain Relief: Relative rapid pain relief, short carryover. can be used as need

Set up:

  • Frequency: 80-125 ppl (or as HIGH as the machine can go)
  • Pulse duration: <100 usec
  • Ampl: Tingling
  • Time: PRN to break pain cycle
15
Q

Endogenous Opiate Theory (description)

A

Pain relief by the RELEASE OF OPIATE-LIKE SUBSTANCES by the body itself (Endorphins)

16
Q

Endogenous Opiate Theory (MOTOR-LEVEL STIMULATION)

  • Modes
  • Indications
  • Pain Relief
  • Set up
A

Modes: LOW FREQUENCY or acupuncture-like TENS **NOT USED FOR ACUTE PAIN)

Indications: sub acute pain, chronic pain

Pain Relief: slow onset of pain relief, longer carryover (hours)

Set up:

  • Frequency: 1-10 pps (lower f than sensory)
  • Pulse duration: >100 usec
  • Ampl: visible contraction (mild motor)
  • Time: 20-30 mins
17
Q

T.E.N.S Parameters

A

Transcutenous electrical nerve stimulation

Parameters

  1. Frequency
  2. pulse duration
  3. amplitude
  4. constant mode
  5. modulation mode
  6. burst mode
  7. timer
18
Q

IFC (description)

A

Interferential Current

  • two medium frequencies AC’s (1-10 KHz)
  • two separate channels with 4 electrodes (quadripolar IFC) *must criss cross in quad IFC
  • Production of BEATS frequency where 2 currents intersect

Unmodulated currents outside machine
Premodulated currents interferes inside machine

19
Q

3 Proposed Advantages of IFC

A
  1. AC sinusoidal currents (>1 KHz) hypothesized to more EASILY PENETRATE SKIN due to reduced skin impedance.
  2. AMPLITUDES OF 2 CURRENTS summate in DEEPER tissue and passing the more superficial sensory afferents nerves.
  3. BEAT FREQUENCY selected for muscle stimulation and pain modulation.
20
Q

IFC (parameters)

A
  1. Frequency
  2. amplitude
  3. constant mode
  4. modulation modes
  5. bipolar/quadropolar switch
  6. Vector scan (modulation of ampl. of one or both channels). manage vectors of intersection
  7. sweep (modulation of frequency)
  8. timer

(compared to TENS, NO PULSE duration in IFC most)